Electrically powered mat-like devices have long been known and used for generating heat for various purposes, and through the course of their development such devices have become quite sophisticated and specialized for particular purposes. The present invention provides a new member of this class of device that is particularly adapted for use for providing a uniform heating source.
The configurational embodiment of heated mats is critical to their practical utility and has not been well addressed by prior devices. Such a mat should be relatively thin to not significantly interfere with the activities of the users. That is, for use in an area in which one stands or sits, the thickness should not create a safety problem by creating a potential for tripping or twisting one's ankle. Further, the mat should be particularly resilient to wear in such an environment where foot traffic and/or chair movement is concentrated on sections of the mat surface. Moreover, where such activity does eventually cause wear in the surface of the mat, visual cues should be provided when that wear has occurred to the point where it potentially causes a problem with the electrical integrity of the mat. The mat should be sufficiently durable to withstand damage which may occur from users wearing stiletto shoes or high heels, or from accidentally dropping a heavy or sharp object. And perhaps most importantly, the mat should be so constructed that the individual user is protected from electrical shock should the electrical circuit of the mat be damaged.
Functionally prior mats have experienced difficulties in providing uniform heat over the entire mat surface and in providing such uniform heat at a temperature comfortable to individual users.
The present invention overcomes these shortcomings of the prior art by providing a heating mat structure which comprises a heating element that is formed of electrically resistive foil that is contained in protective layers of chopped strands and resins. Additional embodiments of the invention further comprise an aluminum earth screen. As an additional safety feature, a color indication is presented to the user should significant wear of the top surface occur.